This invention relates generally to the manufacture of hand tools and, more particularly, pertains to an apparatus and method for forming a wheel blank of a ratchet wrench.
Ratchet wrenches have been found to be extremely effective for tightening and loosening hex-headed fastening elements, such as bolts and machine screws, in a virtually endless range of applications. In this connection, ratchet wrenches have generally been found to be advantageous from a mechanical standpoint since they permit tightening or loosening operations to be carried out with oscillating motions which generally permit users thereof to apply maximum levels or torque to the heads of fastening elements while nevertheless minimizing the amount of work required to perform tightening or loosening operations. However, while ratchet-type wrenches have been found to have significant advantages over other types of wrenches, it has been found that they generally require a conscious effort to prevent slipping off of the fasteners being turned through the wrench wheel or socket engaged about the fastener.
For some years, the assignee of this application has produced ratchet wrenches which address the slipping problem by attaching a washer or retention ring to one side of the wrench wheel. Not only was this a difficult manufacturing process, but it was also inefficient and thereby costly as well.
It is desirable to provide a wrench wheel which will eliminate the need to reposition the ratchet wrench on the heads of fasteners or fittings during tightening and loosening operations. It is also desirable to provide an alternative manufacturing process and apparatus therefor for producing the wrench wheel. Furthermore, it is desirable to provide a ratchet wrench with improved performance and appearance.
One object of the present invention is the provision of a ratchet wrench wheel blank with an integral lip which is folded over in a two-stage bending process.
It is also an object of the present invention to provide an hydraulically operated apparatus for transforming a wheel blank into a rolled retention ring wheel used to improve the overall appearance of a ratchet wrench.
It is a further object of the present invention to provide a reversible ratchet wrench capable of selectively applying clockwise and counterclockwise torques to a polygonal body such as a bolt head or nut without repositioning the wrench thereon.
It is another object of the present invention to provide a ratchet wrench with a rolled wheel blank which facilitates non-slip engagement of a fitting or fastener head throughout tightening and loosening operations.
Another object of the present invention is to provide a ratchet wrench having a sparse number of total component parts.
Another object of the present invention is to provide a ratchet wrench of simplified design and low manufacturing cost.
Still another object of the present invention is to provide an improved ratchet wrench which is of durable and reliable construction and which is attractive to the buying public.
Still another object of the present invention is to provide a ratchet wrench with ends having a domed profile which adds to the aesthetics of the hand tool.
In one aspect of the invention, there is contemplated a method of forming a wrench wheel adapted to be disposed in at least one end of the wrench for engaging an element to be turned. The method includes the steps of providing a wheel blank having a generally hollow, cylindrical body formed with a radially projecting rib located midway between an upper hub portion and a lower hub portion, the upper hub portion being integrally formed with an upstanding lip; and bending the lip inwardly to form a retention ring adapted to engage the upper surface of the element to be turned and to prevent the element from slipping through the wheel of the wrench.
In another aspect of the invention, a ratchet wrench has opposed upper and lower plates defining a plate handle portion with at least one spacer separating the plates, the plates having integral head portions with apertures at the end of the handle portion for supporting and receiving about an axis of rotation sockets adapted to grasp an element to be tightened and loosened. A ratchet structure is provided for locking the sockets in one direction while permitting ratcheting movement in an opposite direction. The improvement resides in each of the sockets including an inwardly bent lip adapted to engage the element to be tightened and loosened in a manner which will prevent the element from slipping through the socket along its axis of rotation. This axis of rotation is generally perpendicular to the head portion of the ratchet wrench.
In another aspect of the invention, a wrench wheel forming apparatus includes supporting structure adapted to seat a generally cylindrical wheel blank having an upstanding lip. A lower forming structure is movable with respect to the supporting structure for initially bending the lip on the wheel blank. An upper forming structure is movable with respect to the supporting structure and the lower forming structure for completing inward bending of the lip of the wheel blank to form a retention ring thereon. The forming apparatus includes intermediate structure disposed between the lower forming structure and the upper forming structure for providing a resistive force therebetween and a guide path therefor. In addition, an actuator structure is provided for vertically moving the upper forming structure.
In yet another aspect of the invention, a wrench wheel forming apparatus includes a stationary pin locator having an upwardly extending locating pin adapted to seat a generally cylindrical wheel blank having an upstanding lip. A vertically movable punch holder having an upper end is adapted to be connected to a hydraulic ram and a lower end is provided with a downwardly depending punch. A vertically movable form insert retainer has a central bore into which the punch extends, the bore receiving a forming insert having a hollow interior in alignment with the bore. The punch holder and form insert retainer have aligned throughbores for accommodating the shoulder bolts which serve to guide the punch holder. A set of die springs surrounds the shoulder bolts and is interposed between a bottom of the punch holder and a top of the form insert retainer.
With this construction, at the beginning of a forming cycle, an upper portion of the forming insert is disposed immediately above the lip of the wheel blank, while the lower portion of the forming insert retainer and the forming insert are held slightly spaced from the stationary pin locator. In a first stage, a hydraulic ram is actuated to move the punch holder such that the die springs will exert a downward force on the form insert retainer enabling the upper portion of the forming insert to provide an initial inward bending of the lip as the lower portion of the forming insert contacts the pin locator and stops travel. In a second stage, the punch holder is moved further downwardly causing the punch to further bend the lip inwardly at a 90xc2x0 as the punch bottoms against the locating pin. The upper portion of the forming insert includes a chamfered surface.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.